Construction Delay Log: What to Record and Keep

TL;DR

A delay log is the day-by-day record that turns "we got held up" into a claim you can support.

Capture the cause, start and end times, the crews and plant affected, and what it stopped you doing.

Attach photos, directions and correspondence as you go, while the evidence still exists.

A consistent log kept during the delay beats a reconstruction written weeks later.

A delay log is not your site diary

A site diary captures everything about the day: weather, who was on site, deliveries, general progress. A delay log is narrower and sharper: it records only delay events and their impact, in enough detail to support a claim. You want both, and they should agree with each other. If you're weighing one against the other, see site diary vs delay record and the records every subcontractor should keep.

What to record in a delay log

Each entry should answer what happened, what it hit, and what it cost. Capture:

The date and time the delay started and ended (or “ongoing”).
The event and its cause, specifically: “access to Level 3 blocked, scaffold not struck”, not “couldn't work”.
The area, activity or programme item affected.
Labour standing: how many, which trades, hours idle or redeployed.
Plant standing: which items, whether on hire, hours idle.
Weather, if relevant, with the actual conditions on the ground.
Any instruction, RFI or variation that caused it or relates to it.
Notices sent or due, with dates.
Evidence attached (photos, dockets, emails) and a rough cost impact.

How to keep one that holds up

Record it the same day. Memory fades and dates blur fast on a live job. Keep it factual and specific rather than emotive; specifics beat adjectives when someone who wasn't there reads it later. Tie each entry to your programme so the effect on completion is visible, and attach evidence as you go. The kind of evidence that supports a claim is far easier to gather in the moment than to reconstruct months later.

Where you keep it matters too. A log scattered across texts, photos and memory is hard to rely on, which is where a lot of common tracking methods fall down. And log the notice, not just the event: a delay carries far less weight commercially if you didn't notify in time, so record what went into your delay notice alongside it.

A quick delay log checklist

Is every delay event dated, with a start and an end (or marked ongoing)?
Is the cause specific enough for someone who wasn't there to understand it?
Have you recorded the labour and plant standing, not just the delay itself?
Is there a photo, docket or email backing each entry?
Did you note the notice you sent, or need to send?

A delay log won't win a claim on its own, but a claim rarely survives without one. Start it on day one, keep it current, and the commercial conversation gets a lot easier when it matters.